Chair frame



FIG. 1 is a front perspective view of a chair frame embodying my new design;

FIG. 2 is a left elevational view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof, and

FIG. 5 is a top plan view thereof. 

The ornamental design for a chair frame, as shown and described. 